Beverage brewing method and apparatus

ABSTRACT

A method for brewing beverages in a machine, which comprises: (a) providing a machine comprising a clamp which is adapted to hold a beverage brewing sachet and a liquid injector tube for injecting liquid into a sachet held in the clamp, wherein the injector tube has a tip and an outlet hole in said tip; (b) providing a beverage brewing sachet containing a beverage brewing ingredient and having at least one side wall region formed of flexible film; (c) inserting the sachet into the clamp; (d) piercing the flexible film in the side wall region of the sachet with the liquid injector tube; and (e) injecting liquid into the sachet through the injector tube to brew the beverage in the sachet, wherein, following step (d), a flap of the flexible film material extends inwardly from said side wall and over the outlet hole of the injector to form a valve that allows liquid to flow into the sachet from the injector tube, but that blocks or restricts the flow of liquid or solid materials into the injector tube from inside the sachet. Also provided is a beverage brewing apparatus for brewing beverages in accordance with the invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a National Stage of PCT/GB02/05575 filed on Dec. 10,2002 claiming priority to GB 0129656.5 filed Dec. 11, 2001.

TECHNICAL FIELD

The present invention relates to methods and apparatus for use inbeverage brewing by liquid injection into a beverage brewing sachet.

BACKGROUND OF THE INVENTION

It is known to brew individual portions of beverages such as coffee andtea from prepackaged individual sachets or capsules containing a singleportion of the beverage brewing ingredient such as ground coffee or leaftea.

The term “sachet” as used in this specification refers to any portionpack containing a predetermined quantity of a beverage brewingingredient. A beverage brewing ingredient may be any form of coffee,tea, hot chocolate or soup or any other type of drink to which liquidcan be added.

GB-A-2121762, EP-A-0179641 and WO99/05036 describe a beverage brewingsystem according to which individual portions of beverage brewingingredients are enclosed in flexible film sachets having an inlet nozzleat the top and a seal at the bottom. In use, hot water is injectedthrough the nozzle into the sachet. The beverage is brewed inside thesachet, and the seal at the bottom of the sachet is opened either beforeor during the brewing to allow the beverage to flow out through thebottom of the seal. This apparatus provides very good quality, freshlybrewed filter coffee, chocolate or leaf tea in individual portions.

PCT/GB01/03978 describes apparatus for the injection of aqueous fluidinto a sachet in which the injector tube or tubes pierce a side wall ofthe sachet to inject the aqueous fluid directly into the interior of thesachet. The injector tube or tubes may project into the brewing cavityat an oblique angle to the exit direction of the beverage cavity, morepreferably substantially perpendicularly to exit direction of thebeverage cavity. PCT/GB01/03978 teaches that the use of sachets withoutnozzles is preferable to the use of sachets with nozzles because of thegreater ease of manufacturing of sachets without nozzles.

One problem associated with brewing beverages using sachets withoutinlet nozzles is that as the injector penetrates the sachet, theinjector comes into contact with the contents of the sachet, which maybe, for example, ground coffee or tea leaves, and the outlet hole of theinjector may become blocked as a result. Furthermore,cross-contamination can occur upon subsequent penetration of a sachetcontaining a different type of beverage by the injector.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a method for brewing beverages in amachine, which comprises:

(a) providing a machine comprising a clamp which is adapted to hold abeverage brewing sachet and a liquid injector tube for injecting liquidinto a sachet held in the clamp, wherein the injector tube has a tip andan outlet hole in said tip;

(b) providing a beverage brewing sachet containing a beverage brewingingredient and having at least one side wall region formed of flexiblefilm

(c) inserting the sachet into the clamp

(d) piercing the flexible film in the side wall region of the sachetwith the liquid injector tube; and

(e) injecting liquid into the sachet through the injector tube to brewthe beverage in the sachet,

wherein, following step (d), a flap of the flexible film materialextends inwardly from said side wall and over the outlet hole of theinjector to form a valve that allows liquid to flow into the sachet fromthe injector tube, but that blocks or restricts the flow of liquid orsolid materials into the injector tube from inside the sachet.

When aqueous fluid is ejected from the injector outlet hole, thehydraulic pressure forces the flap to be displaced from the outlet holeand allows the fluid to enter the sachet. During this injection process,the flow of aqueous fluid forces the contents of the sachet away fromthe outlet hole. Consequently, the contents are not able to come intocontact with the injector outlet hole and block it. When hydraulicpressure is reduced or absent due to the reduction or stoppage ofaqueous fluid being ejected from the injector outlet hole, the nozzleflap can resume its closed position, covering the injector outlet hole.

Preferably, the liquid that is injected through said injector consistsessentially of water, optionally mixed with steam. In certainembodiments the water is injected at a pressure of about 0.5 to about 2bar gauge. In other embodiments, such as in the brewing of espressocoffee, the water is injected at a pressure of about 5 to about 20 bargauge, preferably about 10 to about 15 bar gauge. The temperature of thewater is preferably about 85 to about 100 degrees C.

In certain embodiments the injector tube is movable when the clamp isclosed, whereby the step of piercing comprises moving the injector tubeinwardly into the clamp cavity while the sachet is held in the clamp.

In other embodiments the injector tube projects a fixed distance intothe clamp cavity from a side wall of the clamp, and the step of piercingcomprises pressing the said flexible film region of the sachet againstthe said side wall of the clamp. The pressing may be achieved by thestep of closing the clamp on the sachet, or it may be achieved after theclamp has closed by moving a side wall of the clamp to compress thesachet, for example as described in PCT/GB01/03978. In yet otherembodiments, the step of pressing may be achieved by pressurizing thecontents of the sachet, for example by injecting a fluid into the sachetthrough another inlet.

The side wall of the clamp preferably comprises a recess around theinjector tube, such that the flexible film of the sachet is stretched inthe region of the injector tube by the step of pressing. This stretchingof the sachet wall ensures a more reliable and predictable piercing ofthe sachet.

The present invention further provides a beverage brewing apparatuscomprising: a clamp comprising at least one side wall defining abeverage brewing cavity for receiving a beverage brewing sachet; and aninjector tube extending through the said side wall and having a tip withan outlet hole through which liquid can be injected into the beveragebrewing cavity, the injector tube being adapted to pierce a flexiblefilm wall of a beverage brewing sachet that is pressed against the sidewall, wherein the injector tube and side wall are dimensioned such thatsaid piercing takes place without the tip of the injector tubepenetrating completely into the sachet, whereby a flap of the flexiblefilm wall forms a valve over the tip of the injector tube that allowsliquid to flow into the sachet from the injector tube, but that blocksor restricts the flow of liquid or solid materials into the injectortube from inside the sachet.

Typically, the injector tube has a profiled tip. That is to say, the tipis preferably not flat and parallel to the underlying side wall of theclamp, but angled or pointed, for example in similar fashion to ahypodermic needle. Preferably, the injector tube comprises at least onesharp edge for piercing the sachet. In certain embodiments the injectortube has a substantially planar top surface extending from a sharp edgeof the tip to a trailing edge of the tip, similar to a hypodermicneedle. Preferably, the angle between the perpendicular to this planeand the axis of the injection tube is from about 10 to about 60 degrees,preferably from about 15 to about 45 degrees and most preferably about30 degrees.

Preferably, the injector tube is substantially cylindrical. Preferably,the mean height of the tip of the injector tube above the side wall isfrom about 0.1 to about 5 times the mean outside diameter of theinjector tube, more preferably from about 0.5 to about 3 times the meanoutside diameter. Longer injection tubes will tend to penetrate rightthrough the flexible film material of the sachet and not form thedesired valve flap.

Typically the mean outside diameter of the injector tube is from about 3to 8 mm, and is preferably about 5 mm. Accordingly, the mean height ofthe injector tube is typically from about 1 to 6 mm, preferably about 4mm. The mean outside diameter:mean height ratio for the injector tube isfrom about 8:1 to 1:2, preferably about 5:4. Typically, the mean insidediameter of the injector tube is from about 0.5 to 3 mm, preferablyabout 1 mm. The apparatus may comprise a plurality of said injectortubes preferably having these characteristics.

The injector of the present invention would preferably be made out of arigid material that can be readily shaped so that it can penetrate thematerial from which the sachet or other compartment is made. Thepreferred material from which the injector of the present inventionshould be made is a metal.

The injector projects from a side wall of the clamp. The side wall ispreferably smooth and preferably substantially planar in the vicinity ofthe injector tube. In certain embodiments the side wall of the clampcomprises a recess around the injector tube, whereby the flexible filmof the sachet is stretched in the region of the injector tube by thestep of pressing into the recess. This recess is typically from about 1to about 5 mm deep, preferably about 3 mm, and extends with a meanradius of about 5 to about 25 mm around the injector.

The other elements of the apparatus according to the present inventionmay, for example, be as described in copending applicationPCT/GB01/03978, the entire contents of which are incorporated herein byreference. Alternatively, they may be similar to one of the knownsystems for brewing espresso coffee from capsules, such as thosedescribed in WO93/17932 or WO94/02059, the entire contents of which areincorporated herein by reference.

The beverage brewing ingredient in sachets may comprise or consist of aningredient that disperses completely in hot water, such as instantcoffee, or chocolate, or a concentrated milk, cream, creamer, milkpowder or milk substitute. The beverage brewing ingredient in sachetsmay also comprise or consist of materials that do not completelydisperse in the water used to brew the beverage, for example, groundcoffee or tea. The beverage brewing ingredient may also be in the formof one or more compressed pieces, such as a compressed tablet of groundcoffee. Preferably, the sachet is adapted to brew a single cup ofbeverage.

The present invention further provides a system comprising a beveragebrewing apparatus according to the invention and a beverage brewingsachet comprising at least one side wall region formed from a flexiblefilm. The system is suitable for brewing beverages in accordance withthe invention. The sachet may, for example be a sachet as described inGB-A-2121762, EP-A-0179641 or WO99/05036, the entire contents of whichare incorporated herein by reference.

The apparatus or systems according to the present invention arepreferably adapted for carrying out the methods according to the presentinvention. The methods of the present invention are preferably performedusing an apparatus or system according to the invention as hereinbeforedefined.

BRIEF DESCRIPTION OF THE DRAWINGS

A specific embodiment of the present invention will now be describedfurther, by way of example, with reference to the accompanying drawings,in which:

FIGS. 1( a) and 1(b) show partial schematic cross sectional views ofsteps in the brewing of a beverage using brewing apparatus containing aninjector in accordance with the present invention; and

FIG. 2 shows a detailed schematic cross sectional view of part of FIG.1( b).

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1( a), the sachet comprises a body 2 of athermoplastic sheet material such as a laminate of polypropylene:nylon,EVOH:nylon, or polypropylene:Aluminium:polyethylene, that has beenthermoformed to provide a recess for the beverage brewing ingredient, inthis case ground coffee. The sachet is sealed by a back sheet 1 offlexible, metallized plastic film. A filter paper 9 is bonded into thebody of the sachet, and a tail extension 10 of the sachet extends out ofthe bottom of the clamp to provide an outlet for the beverage brewed inthe sachet.

The sachet is received in a clamp comprising two clamp members 4,5 thatcan be moved together to enclose the sachet. A first clamp member 5comprises an elastomeric membrane 11 supported on a hydraulic reservoir13 as described in PCT/GB01/03978. A second clamp member 4 comprises arigid side wall 14 with a metal injector tube 7 projecting inwardlytherefrom.

The injector tube 7 has a mean height of about 1 mm above the side wall14, and a circular cross-section with a diameter of about 1 mm. The tipof the injector tube is obliquely angled in similar fashion to ahypodermic needle, with the top plane at an angle of about 30 degrees tothe side wall 14, as shown in FIG. 2.

The clamp member includes a rigid spacing element 12 defining a recessaround the injection tube 7.

Referring to FIG. 1( b), upon closure of the clamp 4,5, the hydraulicreservoir 13 is pressurized to press the flexible film face 1 of thesachet against the second clamp member 4. The pressure causes theflexible sheet to bulge into the recess in the clamp member, therebypresenting a tensioned sheet for piercing by the injector tube 7.

When the injector has penetrated the flexible film 1 of the sachet toits maximum extent, the injector outlet hole 7 is still covered by aflap 8 of the sachet film material, as shown in FIG. 2. Thus, theinjector outlet hole is not in contact with the sachet contents 16 butis separated therefrom by the flap 8.

The flap is hinged at the edge 15 of the injector tube 7, and issufficiently flexible that upon injection of liquid through the injectoroutlet hole, the flap 8 is displaced to allow liquid to enter thesachet. When the supply of liquid to the injector tube stops, the backpressure in the sachet presses the flap 8 against the top of theinjector tube 7, thereby preventing any of the contents of the sachetfrom entering the injection tube

The above embodiment of the present invention has been described by wayof example only. Many other embodiments falling within the scope of theaccompanying claims will be apparent to the skilled reader.

1. A beverage brewing apparatus comprising: a clamp comprising at leastone side wall defining a beverage brewing cavity for receiving abeverage brewing sachet; an injector tube extending through the saidside wall and having a tip with an outlet hole through which liquid canbe injected into the beverage brewing cavity, the injector tube beingadapted to pierce a flexible film wall of a beverage brewing sachet thatis pressed against the side wall, wherein the injector tube and sidewall are dimensioned such that said piercing takes place without the tipof the injector tube penetrating completely into the sachet, whereby aflap of the flexible film wall forms a valve over the tip of theinjector tube that allows liquid to flow into the sachet from theinjector tube, but that blocks or restricts the flow of liquid or solidmaterials into the injector tube from inside the sachet.
 2. A beveragebrewing apparatus according to claim 1, wherein the injector tube has aprofiled tip.
 3. A beverage brewing apparatus according to claim 1,wherein the mean height of the injector tube above the side wall is from0.1 to 5 times the mean outside diameter of the injector tube.
 4. Abeverage brewing apparatus according to claim 1, wherein the meanoutside diameter of the injector tube is from 3 to 8 mm.
 5. A beveragebrewing apparatus according to claim 1, wherein the mean height of theinjector tube is from 1 to 6 mm.
 6. A beverage brewing apparatusaccording to claim 1, wherein the mean outside diameter:mean heightratio of the injector tube is from about 8:1 to about 1:2.
 7. A beveragebrewing apparatus according to claim 1, wherein the said side wall ofthe clamp comprises a recess around the injector tube, whereby theflexible film of the sachet is stretched in the region of the injectortube by the step of pressing.